Is the Phillips curve useful for monetary policy in Nigeria?

The objective of this article is to determine if the Phillips curve is a relevant tool to conduct monetary policy in African countries wishing to adopt an inflation-targeting regime. I choose Nigeria as a case of study because it is in the early stage of the implementation of this regime. I estimate a medium-sized model for monetary policy analysis. The model reflects a synthesis between the New Keynesian and the Real Business Cycle (RBC) approaches. Then I estimate the model by using Bayesian econometric technique in order to overcome the shortage of data availability. The study concludes that there is evidence that central banks can control the inflation rate through a Phillips curve, a Taylor rule that includes the exchange rate, and the sterilization of the resources from oil exports. Nevertheless, there are limits to the stabilization program. The same evidence suggests that it is important to implement a credible inflation-targeting regime to reduce inflation gradually, instead of abrupt stabilization attempts with high costs in lost output.Monetary policy, Phillips curve, inflation-target regime.

Alliances and industry analysis

Traditionally alliances have been left at of industry analysis. We have been focusing basically on the economic characteristics determining bargaining power on the relationships between the actors in a value system. The paper proposes a methodology to analyze industries from a very different perspective that incorporates alliances as one of the main drivers of industry structure.Alliances; industry structure; networks;

Theories of gravitation confronted with cosmological observations

[eng] This thesis studies Dark Energy, a central topic of Modern Cosmology, from different points of view. It covers from models and parametrizations to likelihood approximations for the observations of the Large Scale Structure (LSS) of the Universe, which are vital for model constraining, as well as for our study of the S8 tension. The studied model is the α-attractors dark energy model, which reproduces current observations thanks to its capability to mimic a cosmological constant. It is inspired on the Planck-favored inflationary class of models α-attractors and links the inflationary and dark energy periods with the same scalar field. Fortunately, next-generation surveys might be able to distinguish it from ΛCDM by up to 3σ of confidence. Nevertheless, in order to make the most of forthcoming data, we need a formalism that allows us to test models in an efficient way. This could be a observational and theoretical constrained parametrization. We show the case of w0 -wa for thawing quintessence. This parametrization is able to reproduce the observables from recombination to the present when chosen smartly. In addition, their probability distributions built from purely theoretical considerations allow us to restrict the observational bounds to the theoretically motivated area. This work shows how we can work with very general theories such as Horndeski. However, the observational constraints also depend on the correct estimation of their likelihood. Therefore, we have developed (and implemented in NaMaster, from LSST DESC) the Narrow Kernel Approximation (NKA) for the Gaussian (not causally connected) part of the LSS pseudo-Cl covariance matrix. This allows to reproduce accurately the cosmological parameters’ posterior distribution while reducing the computational cost from O(lmax6) (exact computation) to O(lmax3). For sure, the exact computation will be intractable for the next-generation LSS observations, which will resolve really small scales. The NKA has allowed us to start our study of the origin of the S8 tension reported by KiDS-450. With data of LSS from DES and data of CMB from Planck, we want to obtain the temporal evolution of S8 and compare it with that given by KiDS-450 data. Summing up, this thesis has covered dark energy models and developed accurate methods to test their viability in an efficient way. Furthermore, it has gone closer to data and developed the NKA that allows to accurately estimate the LSS likelihood, making it possible for us to study the origin of the S8 tension.[spa] Esta tesis estudia la energía oscura, un tema central en la Cosmología Moderna, desde diferentes puntos de vista. Cubre desde modelos y parametrizaciones, hasta aproximaciones de la likelihood de observaciones de la Estructura a Gran Escala del Universo (LSS), vitales para constreñir los modelos, como para nuestro estudio de la tensión en S8. El modelo estudiado es el de energía oscura de α-attractors, que reproduce las observaciones actuales al poder asemejarse a una constante cosmológica. Inspirado en la clase de modelos de inflación favorecidos por Planck, α-attractors, enlaza el periodo de inflación y energía oscura mediante el mismo campo escalar. Afortunadamente, las misiones futuras podrían diferenciarlo de ΛCDM con hasta 3σ de confianza. No obstante, aprovechar al máximo los datos futuros requiere un formalismo que nos permita comprobar la viabilidad de los modelos eficientemente, como una parametrización acotada observacional y teóricamente. Mostramos el caso de w0-wa para quintaesencia de tipo thawing, que reproduce los observables desde recombinación hasta hoy, si se eligen apropiadamente. Construidas sus distribuciones de probabilidad bajo condiciones puramente teóricas, nos permiten restringir las cotas observacionales a la zona teóricamente motivada. Este trabajo es una muestra de cómo podemos trabajar con teorías muy generales como Horndeski. Pero las cotas observacionales dependen también de una correcta estimación de su likelihood. Por ello, hemos desarrollado (e implementado en NaMaster, del LSST DESC) la Narrow Kernel Approximation (NKA) para la parte gausiana (causalmente no conectada) de la covarianza de los pseudo-Cl de LSS. Ésta permite obtener con exactitud las cotas en los parámetros cosmológicos, al tiempo que reduce el coste computacional de O(lmax⁶) (cómputo exacto) a O(lmax3). Claramente, el cómputo exacto es inviable para las observaciones futuras de LSS que resolverán escalas muy pequeñas. La NKA nos ha permitido empezar a estudiar el origen de la tensión en S8 reportada por KiDS-450. Con datos de LSS de DES y del CMB de Planck, pretendemos obtener la evolución temporal de S8 y compararla con la dada por los datos de KiDS-450. En resumen, esta tesis ha trabajado en modelos de energía oscura y desarrollado métodos precisos para comprobar su viabilidad de manera eficiente. Además, se ha acercado a los datos y desarrollado la NKA que permite estimar precisamente la likelihood para LSS; permitiéndonos estudiar el origen de la tensión en el parámetro S8

The Case for a Countercyclical Rule-based Fiscal Regime

We build a general equilibrium model of a small open economy, with the purpose of analyzing the effects of a countercyclical rule-based fiscal regime, which corresponds to a stylized version of the structural balance in place in Chile. The economy exports a domestically-produced good and one natural resource (commodity), which is partly state-owned, generating income to the government. We analyze how shocks are transmitted to the economy in the presence of this fiscal rule by introducing shocks to government spending, taxes, and the price of the natural resource. In the last shock, we compare our structural rule with a case where the budget is always balanced. The results make a strong case for the adoption of the latter in other commodity exporting economies.open economy, fiscal policy, rule of thumb consumers, government spending.

How Effective is Government Spending in a Small Open Economy with Distortionary Taxes

We build a general equilibrium model of a small open economy, which includes rule-of-thumb consumers, and staggeredd prices and wages, as well as distortionary taxes. The analysis of government spending based on the responses to a government spending shock under three different rules and the sensitivity of several impact multipliers to alternative calibrations. The effect of the shock on consumption and GDP depends on the price elasticity of net exports; the share of rule-of-thumb consumers and domestic goods in the government basket; and finally, the fiscal rule in place. Indeed the response of consumption is more persistent with the rule that adjust spending to close the debt-financed deficit than with the other two rules.open economy, fiscal multiplier, rule of thumb consumers, government spending

Rationale behind the responses of monetary policy to the real exchange rate in small open economies

We estimate how monetary policy works in small open economies. To do so, we build a dynamic stochastic general equilibrium model that incorporates the basic features of these economies. We conclude that the monetary policy in a group of small open economies (including Australia, Chile, Colombia, Peru and New Zealand) is rather similar to that observed in developed countries. Nevertheless, our results also indicate that there are strong differences due to shocks from the international financial markets (risk premium shocks, mainly) that explain mostly the variability of the real exchange rate, which has important reallocation effects in the short run. In addition, we find that in practice central banks do not face any trade-off responding to these shocks through changes in the interest rate. This result is consistent with the fact that in each country under study, the exchange rate must be included in the policy reaction function.small open economy models; monetary policy rules; exchange rates; Bayesian econometrics